Which anticoagulant is used for routine coagulation testing?

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Multiple Choice

Which anticoagulant is used for routine coagulation testing?

For routine coagulation testing, you need an anticoagulant that stops clotting by removing calcium from the plasma, but can be reversed at the time of testing to start the clotting process when measuring times like PT and aPTT. Sodium citrate at 3.2% is used for this purpose. It binds calcium ions, preventing coagulation during collection and handling, while still allowing accurate testing once calcium is reintroduced in the assay. The blood is collected in a ratio that yields platelet-poor plasma, because high platelet counts can contribute to clot formation and skew results. That’s why the specimen is prepared so platelets are below about 10 x 10^9/L. Other anticoagulants either interfere with coagulation measurements or are intended for different tests: EDTA preserves cell morphology for CBCs but isn’t suitable for coagulation studies; heparin can affect clotting times; potassium oxalate is used mainly with fluoride for glucose testing and isn’t appropriate for routine coagulation assays. So, the routine choice is sodium citrate because it preserves the sample by chelating calcium while allowing reactivation of coagulation during the actual assay.

For routine coagulation testing, you need an anticoagulant that stops clotting by removing calcium from the plasma, but can be reversed at the time of testing to start the clotting process when measuring times like PT and aPTT. Sodium citrate at 3.2% is used for this purpose. It binds calcium ions, preventing coagulation during collection and handling, while still allowing accurate testing once calcium is reintroduced in the assay.

The blood is collected in a ratio that yields platelet-poor plasma, because high platelet counts can contribute to clot formation and skew results. That’s why the specimen is prepared so platelets are below about 10 x 10^9/L.

Other anticoagulants either interfere with coagulation measurements or are intended for different tests: EDTA preserves cell morphology for CBCs but isn’t suitable for coagulation studies; heparin can affect clotting times; potassium oxalate is used mainly with fluoride for glucose testing and isn’t appropriate for routine coagulation assays.

So, the routine choice is sodium citrate because it preserves the sample by chelating calcium while allowing reactivation of coagulation during the actual assay.

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